Selections with Repetitions Examples 2

In this class, We discuss Selections with Repetitions Examples 2.

The reader should have prior knowledge of selections with repetitions examples 1. Click Here.

Example:

Given the word misissippi.

A number of four-letter selections from the word Mississippi.

Solution:

s, i repeated four times.

p repeated two times.

Possible selections are given below.

1) four same characters.

2) three same and one different.

3) two same and two different.

4) two same and two different.

4) All different characters.

Four same characters can be selected in two possible ways.

Three same and one different is done in 2 * 3c1 possible ways.

Two same and two different can be selected in 3 * 3c2 ways.

Two same and two same can be selected in 3c2 possible ways.

All different characters can be selected in 1 possible way.

Total selections are 2 + 2* 3c1 + 3 * 3c2 + 3c2 + 1.